Question

I have PDF file data in a SQL Server database, in the column type image (bad previous db designer). What I need to do is read that binary data out to the client, so that they could download the PDF directly to their computer.

So far, my code is as follows:

SqlConnection con = new SqlConnection();
con.ConnectionString = "casIntranetConnectionString";

SqlCommand com = new SqlCommand("SELECT [File], [FileName] FROM [com].[catalog1] WHERE [FileName] = @filename");
com.Connection = con;
com.Parameters.AddWithValue("filename", Request.QueryString["filename"]);

con.Open();

SqlDataReader reader = com.ExecuteReader();

if (reader.Read())
{
    Response.Clear();
    Response.AddHeader("Content-Type", "application/pdf");
    Response.AddHeader("Content-Disposition", "inline; filename=" + Request.QueryString["filename"] + ".pdf");
}

I’m assuming I’m going to need the reader to read out the bytes, but that’s where I don’t really know what I do. Any suggestions?

Thanks!

Answer 1

You can use the HttpResponse BinaryWrite method:

var bytes = reader.GetSqlBytes(index);
Response.BinaryWrite(bytes.Value);

As an aside, please consider separating responsibilities, you have a method which is responsible for accessing the database AND writing to the response. This will lead to maintenance problems in the future. See here for a useful blog post describing SOLID principles. Apologies if your code snippet was contrived, but in case any one else stumbles across this question figured I’d include a “but don’t do it like this” disclaimer!